Articulated center post

ABSTRACT

This invention relates to an occlusion device for the heart, having an articulated center post which allows the device to better conform to the contours of the heart to increase sealing abilities and reduce breakage resulting from conformation pressure.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a division of application Ser. No. 10/348,865, filedJan. 22, 2003, entitled “Articulated Center Post”.

This application is related to U.S. patent application entitled HoopDesign for Occlusion Device, Ser. No. 10/349,118, Occlusion DeviceHaving Five or More Arms, Ser. No. 10/348,701, Septal StabilizationDevice, Ser. No. 10/349,744, and U.S. patent application entitledLaminated Sheets for use in a Fully Retrievable Occlusion Device, Ser.No. 10/348,864, all filed on Jan. 22, 2003.

BACKGROUND OF THE INVENTION

This invention relates to an occlusion device for the closure ofphysical apertures, such as vascular or septal apertures. Morespecifically, this invention relates to an occlusion device for theheart, having an articulated center post which allows the device tobetter conform to the contours of the heart.

Normally, permanently repairing certain cardiac defects in adults andchildren requires open heart surgery, a risky, expensive, and painfulprocedure. To avoid the risks and discomfort associated with open heartsurgery, modem occlusion devices have been developed that are small,implantable devices capable of being delivered to the heart through acatheter. Rather than surgery, a catheter inserted into a major bloodvessel allows an occlusion device to be deployed by moving the devicethrough the catheter. This procedure is performed in a cardiac cathlaband avoids the risks and pain associated with open heart surgery. Thesemodern occlusion devices can repair a wide range of cardiac defects,including patent foramen ovale, patent ductus arteriosus, atrial septaldefects, ventricular septal defects, and may occlude other cardiac andnon-cardiac apertures.

There are currently several types of occlusion devices capable of beinginserted via a catheter including button devices, collapsibleumbrella-like structures, and plug-like devices. A potential draw backto these devices is the difficulty in ensuring that the occluderconforms to the contours of the defect. Poor conformation to the defectresults in poor seating of the device which decreases the ability of thedevice to occlude the defect. Ensuring the proper seating of anocclusion device once it has been deployed poses a continuing challengegiven the uneven topography of the vascular and septal walls of eachpatient's heart. The challenge in designing an occluder which conformsto the uneven topography is compounded by the fact that the contours ofeach defect in each individual patient are unique.

Lack of conformation to the walls of the heart can place significantamounts of stress on the occlusion device and decrease fatigue life.Once deployed, different parts of the occluder may experience more orless stress as a result of the uneven topography. At some point,stressed parts of the occluder may break. Broken parts increase thelikelihood of damage to the surrounding tissue and lead to patientanxiety.

Thus, there is a need in the art for an occlusion device that willocclude cardiac defects and will match the contours of the heart therebyincreasing the life of the device and sealing ability while reducingdamage the surrounding tissue.

BRIEF SUMMARY OF THE INVENTION

The present invention allows occlusion devices to more effectively closea physical anomaly. The present invention is an occlusion device havingan articulated center section. The articulated center section increasesthe ability of the occlusion device to more accurately conform to thedefect. The center section may consist of a post having left and rightparts and a joint which links the left and right parts and providesarticulation. The joint includes a ball carried by a portion of the postand a sleeve forming a socket carried by another portion of the post.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an occlusion device with an articulatedcenter post.

FIG. 2A is a diagram of the heart.

FIG. 2B is a diagram of an occlusion device being inserted into adefect.

FIG. 2C is a diagram of an occlusion device with an articulated centersection being inserted into a defect.

FIG. 2D is a diagram demonstrating the conformation capabilities of anocclusion device with an articulated center.

FIG. 3A is a side view of an articulated center section having twojoints.

FIG. 3B is a side view of an articulated center section having threejoints.

FIG. 4 is a side view of an articulated center section.

FIG. 5 is a side view of a left part of an articulated center section.

FIG. 6 is a side view of a right part of an articulated center section.

FIG. 7 is a side view of left and right sleeves.

FIG. 8 is a cross sectional side view of an assembled articulated centersection.

DETAILED DESCRIPTION

FIG. 1 is a top perspective view of an occlusion device 10. As viewed inFIG. 1, the device 10 comprises a center section 12, proximal and distalfixation devices 14, 30 (each comprised of six arms 16), atraumatic tips18, an proximal sheet 20, and a distal sheet 22. The proximal and distalfixation devices 14, 30 are attached to the sheets 20, 22 using sutures28. The proximal and distal fixation devices 14, 30 are connected to thecenter post 12. One method of connecting the arms 16 to the post 12 isto provide the center post 12 with drill holes through which the arms 16extend. The atraumatic tips 18 are located at the distal end of each arm16 and serve to minimize damage to the surrounding tissue. Theatraumatic tips 18 provide a place for the sutures 28 to attach thesheets 20, 22 to the proximal and distal fixation devices 14, 30. Onemethod of suturing the sheets 20, 22 to the proximal and distal fixationdevices 14, 30 is to provide the atraumatic tips 18 with drill holesthrough which the sutures 28 pass. In this way, the sheets 20, 22 aresewn to the fixation devices 14, 30 at the atraumatic tips 18. Morespecifically, the occlusion device 10 is constructed so that theproximal and distal fixation devices 14, 30 are easily collapsible aboutthe center section 12. Due to this construction, the occlusion device 10can be folded so that the fixation devices 14, 30 are folded in theaxial direction. The proximal and distal sheets 20, 22 attached to theproximal and distal fixation devices 14, 30 are flexible, and canlikewise collapse as the proximal and distal devices 14, 30 are folded.In addition, the center post 12 further comprises a knob 24. The knob 24allows for the device 10 to be grasped as it is inserted into the bodythrough the catheter.

Once the device 10 is deployed, the fixation devices 14, 30 serve tohold the proximal and distal sheets 20, 22 in place to seal the defect.To ensure there is sufficient tension to hold the sheets 20, 22 inplace, the fixation devices 14, 30 are made of a suitable materialcapable of shape memory, such as nickel-titanium alloy, commonly calledNitinol. Nitinol is preferably used because it is commerciallyavailable, very elastic, non-corrosive and has a fatigue life greaterthan that of stainless steel. To further ensure that the fixationdevices 14, 30 do not suffer from fatigue failures, one embodiment ofthe present invention relies on making the wire fixation devices 14, 30of stranded wire or cables.

The center section 12 shown in the device 10 is articulated. Thearticulation can be accomplished by a variety of methods. Thearticulation could comprise one or more joints, or hinges. It could alsobe a spring or a coil. Additionally, a spot specific reduction in theamount of material used to create the center section 12 could renderportions of the section 12 sufficiently flexible.

The center section 12 is preferably formed to have a diameter of betweenabout 8 millimeters and about 0.1 millimeters. In addition, the lengthof the center section is preferably less than about 20 millimeters.

The sheets 20, 22 are comprised of a medical grade polymer in the formof film, foam, gel, or a combination thereof. One suitable material isDACRON®. Preferably, a high density polyvinyl alcohol (PVA) foam isused, such as that offered under the trademark IVALON®. To minimize thechance of the occlusion device 10 causing a blood clot, the foam sheets20, 22 may be treated with a thrombosis inhibiting material. One suchsuitable material is heparin.

The size of the sheets 20, 22 may vary to accommodate various sizes ofdefects. When measured diagonally, the size of the sheets 20, 22 mayrange from about 15 millimeters to about 45 millimeters. In someinstances, it maybe desirable to form the sheets 20, 22 so that they arenot both the same size. For instance, one sheet and its associatedfixation device can be made smaller (25 millimeters) than thecorresponding sheet and its associated fixation device (30 millimeters).This is particularly useful in situations where the occlusion device 10is to be placed at a location in the heart which is close to othernearby cardiac structures. Making the sails 20, 22 different sizes mayassist in providing optimal occlusion of a defect, without affectingother structures of the heart which may be nearby.

FIGS. 2A through 2D illustrate the method by which the occlusion device10 is deployed. FIG. 2A is a diagrammatic view of a human heart 30.Visible in FIG. 2A is the right atrium 32, the left atrium 34, the rightventricle 36, the left ventricle 38. The right atrium 32 is separatedfrom the left atrium 34 by a atrial septal wall 40. The right ventricle36 is separated from the left ventricle 38 by a ventricular septal wall42. Also visible in FIG. 2A is an atrial septal defect 44 located in theatrial septal wall 40, between the right atrium 32 and left atrium 34 ofthe heart 30. An atrial septal defect 44 is one example of a cardiacdefect that may be occluded using the occlusion device 10.

FIG. 2B is a more detailed view of the septal wall 40 and the defect 44,shown between the right atrium 32 and the left atrium 34. Also shown isthe occlusion device 10 of FIG. 1, a catheter 50, and a delivery forceps52. As viewed in FIG. 2B, the occlusion device 10 comprises a distalside 54, a proximal side 56, and a center section 12. The occlusiondevice 10 is being inserted into the septal defect 44 from the catheter50. The device 10 is tethered to the delivery forceps 52. To insert theocclusion device 10, the catheter 50 is positioned proximate the septaldefect 44. Next, the delivery forceps 52 is used to push the occlusiondevice 10 through the catheter 50 so that the distal side 54 of thedevice 10 unfolds in the left atrium 34. Although the distal side 54 hasbeen deployed, the proximal side 56 is still folded in the catheter 50.

The placement of the catheter 50, or other means that guides the device10 to the defect 44, determines the location of and angle at which theocclusion device 10 is deployed. Once the catheter 50 is properlypositioned at the defect, the delivery forceps 52 is used to push thedevice 10 through the defect 44. The distal side 54 of the device 10 isthen allowed to expand against septal walls 40 surrounding the defect44.

In FIG. 2 B, the center section 12 is articulated but the articulationremains inside the catheter 50 and is therefore immobilized. If thecenter section 12 of the occlusion device 10 is not articulated (orarticulated but immobilized), the device's center section 12 must enterthe defect 44 following the same angle of insertion as the catheter 50or other delivery device. As a result, the insertion angle is limited bythe catheter's angle of insertion FIG. 2B.

Often, due to limited space, the catheter 50 enters the heart at anangle that is not perpendicular to the defective wall FIG. 2B. In thissituation, the device 10 cannot enter the defect 44 properly because theline of the center section 12 must follow the same line as the catheter50. The device 10 must be forced into the defect 44 at an angle, whichmay cause the tissue surrounding the defect 44 to become distorted. Ifthe surrounding cardiac tissue is distorted by the catheter 50, it isdifficult to determine whether the device 10 will be properly seatedonce the catheter 50 is removed and the tissue returns to its normalstate. If the device 10 is not seated properly, blood will continue toflow through the defect 44 and the device 10 may have to be retrievedand re-deployed. Both doctors and patients prefer to avoid retrieval andre-deployment because it causes additional expense and longer proceduretime.

FIG. 2C shows an occlusion device 10 with an articulated center section12 being inserted into a cardiac defect 44. Shown once again are thedefect 44, septal walls 40, catheter 50, and occlusion device 10comprising a distal side 54, and a proximal side 56. In FIG. 2C, theocclusion device 10 has been further advanced through the catheter 50 toexpose the articulated center section 12 comprising a joint 62.

When the center section 12 is articulated or flexible, the insertionangle of the device 10 is not restricted to that of the catheter 50. Thedevice 10 can be more easily inserted, because once the joint 62 isoutside the catheter 50, the angle of insertion can be changed byallowing the joint 62 to move. This variable insertion angle allows thedevice 10 to enter the defect 44 at an optimum angle, minimizingdistortion of surrounding cardiac tissue. If the tissue is not distortedwhen the device 10 is deployed, the seating of the device 10 should notchange drastically once the catheter 50 is removed. Because the device10 can be properly seated at the first insertion, the number of casesthat require retrieval and redeployment should decrease.

FIG. 2D shows an occlusion device 10 having an articulated centersection 12 that is fully deployed and is occluding a cardiac defect 44.Shown in FIG. 2D is a distal side 54, a proximal side 56, a center post12, a joint 62, septal walls 40, and a defect 44. The distal side 54 hasbeen properly positioned, the proximal side 56 has been deployed and thedevice 10 has been released. FIG. 2D demonstrates the ability of anocclusion device 10 having an articulated center section 12 to conformto an irregularly shaped defect 44.

Another important advantage of the present invention is that thearticulated center section 12 allows the distal and proximal sides 54,56 to conform more readily to the contours of the heart 30 after it isdeployed, providing a custom fit to a variety of defects. Often, whenimplanted, an occlusion device 10 is located in an irregularly shapeddefect 44. Having an articulated center section 12 allows the occlusiondevice 12 to fit in a wider variety of defects, despite the shape orsize of the defect.

For instance, as viewed in FIG. 2D, the septal wall 40 on the bottom ofthe defect may be only a few millimeters thick, but on the top may bemany more millimeters thick FIG. 2D. In such cases, one side of theoccluding device 10 may be bent open further than the other side. Theside that is more distorted carries a high static load which bothincreases pressure on the surrounding tissue and increases thepossibility of breakage of the device 10. If the center section 12 isarticulated, it can bend such that the upper or lower fixation devices14, 30 need not be the only the only parts which adjust to fit thedefect 44. The ability to conform to a variety of heart contoursprovides better seating, reduces tension (increasing fatigue life), anddecreases the likelihood of damage to tissue resulting from breakage andfrom pressure the device places on surrounding tissue.

Another feature of the occlusion device 10 is that it is fullyretrievable. To allow the device 10 to be retrievable, as well as ensurethat the device 10 fits into as small a diameter catheter as possible,it is important to ensure that the arms 16 are not of a length thatresults in the tips 18 clustering at the same location. If the tips 18all occur at the same location when the device 10 is inside the catheter50, the device will become too bulky to allow it to be easily movedthrough the catheter.

In situations where the occlusion device 10 is not properly deployed andmust be retrieved into the catheter 50, it is possible to withdraw theocclusion device 10 back into the catheter 50 by grasping either thecenter section 12 or by grasping any one of the arms 16. When the device10 is retrieved into the catheter 50, both the upper and lower arms 16will be folded in the same direction. In such an instance, it islikewise important to vary the length of the upper arms from the lengthof the lower arms 16 so that when the device 10 is retrieved, the tips18 on both the upper arms 16 do not cluster at the same location as thetips 18 on the lower arms 16.

FIG. 3A is a perspective view of an example of an articulated centersection 70 with double articulation. As viewed in FIG. 3A, the centersection 70 comprises a right part 72, left part 74, and a center part76. The left part 74 has a knob 24 located on one end. Both right andleft parts 72, 74 have three holes 80 drilled through them. The centersection 70 further comprise two joints or hinges 78 on each end of thecenter part 76. The joints or hinges 78 connect the right and left parts72, 74 to the center 76 and allow for the right and left parts 72, 74 torotate relative to the center part 76. The wire arms 16 (FIG. 1) attachto the center section by passing through the holes 80 drilled throughthe left and right parts 72, 74.

In this example, a joint 78 provides the articulation. Though shown witha double articulation, the articulated center section 70 is not solimited. The number of joints or hinges 78 maybe varied to accommodate aparticular defect or a particular type of defect. For example, one jointor hinge may be best for an atrial septal defect while two or threearticulations may be best for a larger defect such as patent foramenovale or a long defect such as patent ductus arteriosus.

The articulation may be achieved in a variety of ways. Ball joints orhinges may create the articulation. The articulation may also be createdby the addition of a spring like coil to the center, a reduction of theamount of material used in a portion the center, or use of material thathas ample flexibility when constructing the center.

In addition, it is possible to provide the center section with more orless articulations. FIG. 3B is a side view of an articulated centersection 90 with triple articulation, which demonstrates the range offlexibility of the joints 100. Shown is a right part 92, a left part 94with a knob 24, two center parts 96, a joining part 98, and four joints100. The large amount of flexibility allows the occlusion device toconform to a wide variety of defects. If less flexibility is needed, ancenter section 90 with one or two joints may be preferred.

FIG. 4 is an enlarged side view of one example of an articulated centersection 70, showing the section 70 in more detail. The articulatedcenter section 70 is comprised of a right part 72, a left part 74 whichhas a knob 24, a center part 76, and two joints 116, 118. The centerpart 76 is comprised of a left sleeve 112 and a right sleeve 114. Theleft part 74 connects to center section 76 at the left joint 116. Theright part 72 connects to the center part 76 at the right joint 118.

The joints or hinges 116, 118 allow the right and left parts 72, 74 torotate relative to the center part 76, giving them a full 360° of motionrelative to the center part 76. Preferably, the joints or hinges 116,118 are designed to allow for maximum three dimensional movement of boththe right and left parts 72, 74 relative to the center part 76. However,the joints 116, 118 may also be configured to provide two dimensionalmovement of the right and left parts 72, 74 relative to the center part76. The range of motion need not be a full 360° to be an improvement.Other ranges of motion, such as two dimensional rotation may work also,depending on the type of defect.

FIG. 5 is an enlarged side view of the left part 74. The left part 74comprises a ball 120, a first neck 122, a cylindrical body 124, a secondneck 126, a knob 24, and three holes 80. As described above, three holes80 are drilled through the part 74 to allow for attachment of the wirearms 16.

The end ball 120 on one end of the left part 74 is connected to thecylindrical body 124 of the left part 74 at the first neck 122. The knob24 is located on the other end of the cylindrical body 124 and isconnected to the body 124 by a second neck 126. To assist in assembly,discussed in more detail below, the cylindrical body 124 of the leftpart 124 is preferably smaller in diameter than the ball 120. The knob24 has a smaller diameter than both the body 124 and the ball 120. Forexample, the end ball 120 may have a diameter A of about 1.35millimeters, the cylindrical body 124 may have a diameter B of about 1.2millimeters, and the knob 24 may have a diameter C of about 1.0millimeter.

The knob 24 is configured to allow a delivery forceps 52 to attach tothe occlusion device 10 as it is pushed through the catheter 50 andallows the forceps to manipulate the device 10 as it is delivered.Likewise, a guide forceps can be used to position the occlusion device10 once it reaches the desired location or to retrieve the device 10should it not be seated properly. The knob 24 may additionally have across sectional area which allows the forceps to rotatably move thedevice while the device is inserted into a defect 44. The second neck126 is grasped by a forceps so that there is at least some play betweenthe forceps and the second neck 126 when pushing the device through acatheter. For example, the guide forceps may engage the second neck 126by means of a claw-like or hook-like end. In an alternate embodiment,the knob 24 is threaded to allow for attachment to a threaded guideforceps.

FIG. 6 is a side view of a right part 72. The right part 72 comprises aball 130, a first neck 132, a cylindrical body 134, and three holes 80.Once again, three holes 80 are drilled through the part 72 to allow forattachment of the wire arms 16.

The right part 72 is nearly identical to the left part 74 except that itdoes not require a knob 24 or second neck 86. Because the occlusiondevice 10 only needs to be graspable at one end, a second knob isunnecessary. To assist in assembly, the cylindrical body 124 of the leftpart 124 is preferably smaller in diameter than the ball 120. Forexample, the end ball 130 may have a diameter D of about 1.35millimeters, and the cylindrical body 134 may have a diameter E of about1.2 millimeters.

FIG. 7 is an exploded view of the center section. Shown is a rightsleeve 112 and a left sleeve 114. The right sleeve 112 comprises a cuff140. The cuff 140 is configured to fit inside the left sleeve 114 whenthe two sleeves are assembled. As shown more clearly on FIG. 8, the twosleeves 112, 114, once assembled, the two sleeves 112, 114 can bepermanently attached at the cuff 140, and secured by welding.

FIG. 8 shows a cross sectional view of an assembled articulated centerpost. Shown is the left part 74, the right part 72, and the center part76, which comprises the left sleeve 114, and the right sleeve 112 havinga cuff 140. Also shown is a washer 150. Each sleeve has a sleeve opening152. Also shown are the details of the left and right parts: a knob 24,a second neck 126, first necks 122, 132, cylindrical bodies 124, 134,end balls 120, 130, and holes 80. The sleeves 112, 114 have been weldedtogether.

To assemble the center post, the left and right parts 74, 72 are slippedinto the corresponding left and right sleeves 114, 112. As describedabove, the diameter of balls 120, 130 is less than the diameter ofbodies 124, 134. As a result, the cylindrical bodies 124, 134 are smallenough to fit through the sleeve openings 152, 154 but the end balls120, 130 are too large to fit through the sleeve openings 152, 154.Once, the left part 74 is placed through the left sleeve 114, thecylindrical body 124 extends out the sleeve opening 152 but the end ball120 remains inside the sleeve 114. Similarly, once the right part 72 isslipped through the right sleeve opening 154, the body extends out thesleeve 112 but the end ball 120 remains inside the sleeve 112. Thewasher 150 may be inserted at the end of the cuff 140 of the rightsleeve 112. Next, the left sleeve 114 and the right sleeve 112 arejoined by inserting the cuff 140 into the left sleeve 114. Onceassembled, the sleeves 112, 114 are welded together.

The resulting assembly forms two ball joints which are able to rotateindependently of each other relative to the center part 76. The firstnecks 122, 132 sit at the sleeve opening 152, 154 after the cylindricalbodies 124, 134 have been pushed through the corresponding sleeveopenings 152, 154. The diameters of the necks 122, 132 are smaller thanthe diameter of the sleeve openings 152, 154 so the necks 122, 132 haveample space to rotate freely in the sleeve openings 152, 154. The endballs 120, 130 are separated by the washer 150 so that they do not comein contact with each other and restrict each other's movement. Thewasher 150 also prevents the end balls 120, 130 from moving too far intothe center of the sleeves 112, 114. If the end balls 120 were allowed tomove too far back into the sleeves 112, 114, the left and right parts74, 72 could also move into the sleeves 112, 114, thereby restrictingthe movement of the joints 116, 118. Preferably, a hard metal, such astitanium, is used to construct the parts of the center post because useof a hard material prevents binding within the ball joints.

There may be occasions where an occlusion device with singlearticulation or one joint is preferred. In one embodiment a neck 122,132 is welded in place in the sleeve opening 152, or formed integrally,to immobilize one joint if only a single movable joint is desired.Alternatively, one of the end balls 120, 130 could be welded to thewasher 150 to immobilize one of the joints.

Though shown in a patent foramen ovale occlusion device, an articulatedcenter post can be adapted for use in any occluding device, includingthose designed for atrial septal defects, patent ductus arteriosus, andventricular septal defects. The center post can also be adapted for usein an septal stabilization device.

Although the present invention has been described with reference topreferred embodiments, workers skilled in the art will recognize thatchanges may be made in form and detail without departing from the spiritand scope of the invention. In particular, any of the applicablefeatures disclosed in related applications U.S. patent applicationentitled Septal Stabilization Device, Ser. No. 10/349,744, U.S. patentapplication entitled Hoop Design for Occlusion Device, Ser. No.10/349,118, Occlusion Device Having Five or More Arms, Ser. No.10/348,701, and U.S. patent application entitled Laminated Sheets forUse in a Fully Retrievable Occlusion Device, Ser. No. 10/348,864, may beof use in the present invention. Each of these applications is herebyincorporated by reference.

1. An occlusion device for the closure of a physical anomaly, the devicecomprising: a first occluding body connected to a first supportstructure; a second occluding body connected to a second supportstructure; and a center post connecting the first and second supportstructure, the center post including a ball and socket joint.
 2. Anocclusion device comprising: a jointed center strut including a firststrut section having a body, a neck and a ball, and a first sleevehaving a socket that forms a ball and socket joint with the ball of thefirst strut section and an opening through which the neck extendsbetween the ball and the body; a first plurality of fixation devicesextending from the body of the first strut section of the jointed centerstrut; and a first sheet attached to the first plurality of fixationdevices.
 3. The occlusion device of claim 2 wherein the center strutfurther includes a second strut section having a body, a neck and aball, and a second sleeve having a socket that forms a ball and socketjoint with the second strut section and an opening through which theneck extends between the ball and the body.
 4. The occlusion device ofclaim 3 and further comprising: a second plurality of fixation devicesextending from the body of the second strut section.
 5. The occlusiondevice of claim 4 and further comprising: a second sheet attached to thesecond plurality of fixation devices.
 6. An occlusion device comprising:a jointed center strut having distal and proximal ends, the jointedcenter strut having a plurality of ball and socket joints; a first setof wire support arms extending from the first part distal end of thejointed center strut; a first sheet attached to the first set of arms; asecond set of wire support arms extending from the proximal end of thecenter strut; and a second sheet attached to the second set of supportarms.
 7. An occlusion device comprising: a jointed center piece having aplurality of ball and socket joints; first and second collapsiblesupport frames spaced from one another and extending from the jointedcenter piece; and first and second sheets attached to the first andsecond collapsible support frames respectively.